This application proposes to identify the gene(s) contributing to the 6q linkage peak that has been identified in African American families that have type 2 diabetes mellitus (T2DM). The positional cloning method will be used to evaluate and determine potential candidate genes in this region. We believe we have identified a novel diabetes gene in this region, Estrogen Receptor alpha (ESR1), which would represent the first diabetes gene positionally identified using data from an African American population. We aim to further explore single nucleotide polymorphisms and haplotypes that show association with T2DM in ESR1, as well as analyze SNPs in additional candidate genes, in order to determine if there is any association in those genes as well. Association findings will then be analyzed through functional assays to determine if there is the associated SNPs/haplotypes serve a biological function. Understanding how polymorphisms in ESR1, or any other candidate genes located under the 6q linkage peak, will provide critical information that will aid in understanding the pathophysiology of T2DM and how these variations contribute to the disease across different populations.